"Spawned by strangely cold temperatures, 'beautiful' clouds helped strip the Arctic atmosphere of most of its protective ozone this winter, new research shows.

The resulting zone of low-ozone air could drift as far south as New York, according to experts who warn of increased skin-cancer risk.

The stratosphere's global blanket of ozone—about 12 miles (20 kilometers) above Earth—blocks most of the sun's high-frequency ultraviolet (UV) rays from hitting Earth's surface, largely preventing sunburn and skin cancer.

But a continuing high-altitude freeze over the Arctic may have already reduced ozone to half its normal concentrations—and 'an end is not in sight,' said research leader Markus Rex, a physicist for the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany."

Christine Dell'Amore reports for National Geographic News March 22, 2011. [2]